Crude membranes of influenza virus-augmented tumor transplantation antigen (TTA) used an an immunotherapeutic agent, suppressed tumor growth especially in combination with surgical exicision of the primary tumor and chemotherapy in mice. Nearly 40 BALB/c cultured tumor lines which were transformed either in vivo or in vitro were classified into three types according to tumorigenicity in vivo (in syngeneic mice) and/or in vitro (in soft agar). The first one is that tumors grew both in mice and in soft agar, and the second is the tumors could grow in soft agar but not in mice. The third is that tumor did not grow in soft agar even though they were highly tumorigenic in mice.